On 03-07-18, 09:10, Timur Tabi wrote:
> On 7/3/18 1:04 AM, Vinod Koul wrote:
> > Add support for probing on ACPI systems, with ACPI HID QCOM8160.
> >
> > On ACPI systems, clocks are always enabled, the PRNG should
> > already be enabled, and the register region is read-only.
> > The driver only verifies that the hardware is already
> > enabled never tries to disable or configure it.
> >
> > Signed-off-by: Timur Tabi<timur@xxxxxxxxxxxxxx>
> > [port to crypto API]
> > Signed-off-by: Vinod Koul<vkoul@xxxxxxxxxx>
>
> I've asked a colleague who still works at Qualcomm to test this code on
> silicon. It looks okay, but I just want to be sure.
>
> > + /*
> > + * ACPI systems have v2 hardware. The clocks are always enabled,
> > + * the PRNG register space is read-only and the PRNG should
> > + * already be enabled.
> > + */
> > + if (has_acpi_companion(&pdev->dev)) {
> > + val = readl(rng->base + PRNG_CONFIG);
> > + if (!(val & PRNG_CONFIG_HW_ENABLE)) {
> > + dev_err(&pdev->dev, "device is not enabled\n");
> > + return -ENODEV;
> > + }
>
> I'm having second thoughts about this PRNG_CONFIG_HW_ENABLE check. The PRNG
> on the QDF2400 is the same as the one on the 8996, so it should have the
> same register interface. Currently, the ACPI table points to a full PRNG
> register block, but I'm beginning to believe that it should instead point to
> a "reduced" block that doesn't have a PRNG_CONFIG register.
That was my doubt too. I will go ahead and make it skip this then...
--
~Vinod
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